A lighting module of this type is known, for example, from Japanese Patent Application JP 61-147585, which describes a module comprising a LED supported on a mount, and a total-internal-reflection lens having a recess in which the LED is housed; and both the lens and the LED are housed in a cylindrical casing. By housing the LED/lens assembly inside a casing, this and other similar modules (a further example is described in U.S. Pat. No. 6,274,924) are difficult to produce, mainly on account of the necessity to assemble and connect the various component parts (the lens, in particular, is normally glued), and also have the major drawback of failing, in use, to effectively disperse the heat generated by the LED.
The problem of effectively cooling the LED is further compounded when the LED is housed inside a recess in the lens, in which case, dissipating plates fitted to the LED mount may not always be sufficient.
A further drawback lies in the lens normally being molded in a one-piece body from transparent polymer material. And since the lens is relatively thick, with an axial dimension comparable (i.e. substantially equal to or greater than) the transverse dimension, a relatively long molding time is required.
Moreover, the efficiency of total-internal-reflection lenses (and, therefore, of lighting modules equipped with them) is greatly affected by the condition of the reflecting surface, and may be impaired in the event the surface is damaged or even only contaminated. The problem therefore arises of effectively protecting the reflecting surface, both in use and, above all, when manufacturing and handling the lens and assembling the lighting module.